How do Elizabeth and John influence Hale's change in Act 2 of The Crucible?

Once Hale gets to intimately know Elizabeth and John, a change emerges in his characterization.  As he changes his perspective on what is happening in Salem, it becomes easier for us to share his doubts.

Hale arrives in Salem convinced that witchcraft is being practiced.  In Act II, Hale sits down with the Proctors and talks to them about their own lives in Salem.  Before leaving, Hale is "struck" with the revelation that the children's sicknesses have "naught to do with witchcraft."  Hale is slowly beginning to have doubts, encouraged by Proctor's revelation. He recognizes that the machinery of the trials might be operating outside of divine will:

Proctor: And why not, if they must hang for denyin’ it? There are them that will swear to anything before they’ll hang; have you never thought of that? 

Hale: I have. I - I have indeed. It is his own suspicion, but he resists it. He glances at Elizabeth, then at John. 

Talking with John and Elizabeth has begun the process of slowly changing Hale's perspective on what is happening in Salem.

In addition to this, Hale begins to see the emotional intensity between John and Elizabeth.  Francis Nurse and Giles Corey enter the scene.  They are shocked and saddened their wives have been apprehended.  This experience is repeated between Proctor and Elizabeth, when she is arrested.  Hale is taken aback by the emotion of Elizabeth being arrested.  Proctor's intensity to prove his wife innocent leaves an impression upon him.  These emotional revelations contribute to changing his point of view.

As Hale changes because of what he sees, so do we.  When we see how Elizabeth bids farewell to her children and how Proctor vehemently defends her, we recognize the human cost to the trials. We begin to share Hale's "suspicion" that the system is out of control.  As so many people are being apprehended, Hale's suspicions are our own. 

How do Elizabeth and Hale react differently to John's choice of death in The Crucible?

In The Crucible, Elizabeth Proctor and Reverend Hale have differing opinions about John Proctor’s decision to die, yet both end up respecting his courage. Hale strongly believes that John, Elizabeth’s husband, should confess to save his life. Hale strongly encourages Elizabeth to try to convince him to confess. She will not promise Hale that she will plead with John.

When Elizabeth meets her husband in the jail, she is ambivalent but assures him that she does not judge him and will support whatever decision he makes, because it his soul, not hers, that is in peril. At this point, John decides he will confess, even though he considers it evil.

After he writes and finally signs the confession, however, John refuses to turn it over to Danforth. Instead, he tears it up. Hale is furious, and Elizabeth, distraught, weeps. As John and Rebecca Nurse are led away, Hale dismisses his decision as pride that will bring him shame. Elizabeth disagrees, and her distress turns to admiration. She has the last words, firmly stating that it is not for her to take John’s goodness away from him.

How does Elizabeth influence John in The Crucible?

Elizabeth asks John to consider his conscience.  She tells him that many people have confessed and been let go.

When John Proctor is sentenced to be hanged in Act 4, Reverend Hale asks Elizabeth: “Will you plead with him?” (act 4).  He wants her to use her influence as his wife to convince him to change his testimony.  If John confesses, they will not hang him.  Elizabeth and John’s relationship has suffered since his affair.

John asks Elizabeth if he should confess, but Elizabeth does not give him the answer he wants.

As you will, I would have it. I want you living, John. That's sure. Do what you will. But let none be your judge. There be no higher judge under Heaven that Proctor is! Forgive me, forgive me, John-- I never knew such goodness in the world! (Act 4)

She reminds him that he has to answer to his conscience.  She wants him alive, but she does not want him to swear under oath to something that is not true.  John does choose to testify, but he regrets it almost immediately.  He knows that his testimony will be a lie, and therefore a sin, and it will rest on his conscience.